Can't get my threads to run at the same time :-(

Question

Hi,
I hope someone can help me. I have an two instances of an object that extends thread. In it's run method, there is a while loop that iterates while an int x (that starts at about 450) is not less than 0.
In the while loop there is an x--; statement.
Also inside the while loop is a call to yield();
Also is a call sleep(5);
Also in the while loop is a statement something like "System.out.println(x);"
The int controls the vertical position of an icon (a JLabel) on the screen.
In the class that has the main method, two instances of the thread object are created one after the other and run one after the other, although the program keeps running the first one until it has finished before running the second one!
For example, the code looks something like this:-
o1.run();
System.out.println("o1 running");
o2.run();
System.out.println("o2 running");
And the end printout (with the println call from the thread objects) looks like this:-
o1 running
450
449
448
3
2
1
o2 running
450
449
etc.
What's going on? Why won't it start running the second thread straight after the first one?
Any help appreciated!

Answer 1

class test extends Thread {
  private int i = 0;
  private String strMess = new String("");
  public static void main (String[] args)  {
     test t = new test("first");
     t = new test("second");
  test(String strIn){
       this.strMess = strIn;
       this.start();
  public void run(){
       while(i<5){
          System.out.println(this.strMess + i);
          try{this.sleep(200);}catch(Exception e){e.printStackTrace();}
          i++;
}output:
first0
second0
first1
second1
first2
second2
first3
second3
first4
second4
class test extends Thread {
  private int i = 0;
  private String strMess = new String("");
  public static void main (String[] args)  {
     test t = new test("first");
     t = new test("second");
  test(String strIn){
       this.strMess = strIn;
       this.run();
  public void run(){
       while(i<5){
          System.out.println(this.strMess + i);
          try{this.sleep(200);}catch(Exception e){e.printStackTrace();}
          i++;
}output:
first0
first1
first2
first3
first4
second0
second1
second2
second3
second4